Need help Identifying this 18" RCF driver.

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athlon64

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Joined 2014
#1
Hello there.
Long story short. My father used to have a disco club (1997 - 2001.) we recently got all the equipment from the club back after it's been stored for over 10 years and not used.

Now all the equipment was produced by the italian company "peecker sound" 4x 900w (4ohm) amps. 4x500w (4ohm) amps. Running 4 18 inch peecker sound woofers and 4 mid-hii 12+horn peecker sound speakers. R
ecently i started restoring the equipment so i can start renting it.
It's all working very well. I spent about 30 hours cleaning the amps and we tested it all outside with a DJ:

https://fbcdn-sphotos-h-a.akamaihd....0_10202625694784276_4804679082402610285_o.jpg

Now finally here is my question. The drivers in these speakers seem to be in perfect condition. And damn they sound good! But i just can't find any specifications (except the 8ohm impedance rating). And i'd really like the datasheet for these drivers. Now when i took them out i soon realised they look exactly the same like some RCF drivers.

There is a good chance that these are RCF drivers. On the back there is a "acoustic research labs" sticker. But that is just a section of peecker sound company so it doesn't tell me much. They however look exactly the same like some RCF speakers. On the 18 woofer there is an engraving:

L121000

i know some RCF speakers are marked with L12 right?
I wanted to send you some pictures of these drivers to ask you if you could please help ne indentify them. Guys from peecker sound don't reply the emails. If you recognise these 18 an 12 drivers please give me the models thank you very very much.

Here are the pics

Peecker Sound Oprema Photos by athlon-64 | Photobucket

So i seem to have found one of the drivers. The 12" inch in the mid-hii speaker seems to be an
RCF L12-544k

on the back of each one of my speakers there is a number engraved. On the 12' speaker it was L121001. When i first saw the L12-544k online i realised it looks the same. Then i saw the number and finally... that is the speaker.

Now i still haven found my 18's and i have another question. Are these genuine RCF drivers or are these copies from peecker sound? Either way they sound damn fantastic but considering the engraved number. The fact that drivers are absolutley identical and both produced in Italy. I think this is and RCF with a different sticker right ??

So here is my 12 driver:

http://i30.photobucket.com/albums/c316/athlon-64/peecker sound oprema/IMG_2458_zps390461a0.jpg

and here is a L12-544k that i found online:

http://mla-s2-p.mlstatic.com/9134-MLA20013034555_112013-O.jpg

Parlantes Rcf L12-544k (De 310 Watts hasta 500 Watts) a ARS 3300 en PrecioLandia Argentina (81gozc)

Take a good look at the engraved number on this RCF that i linked and my driver and you'll see it's the same number. So is this a genuine RCF driver from 1997 ?

Also can you help me find these 18's i have :/
 
#2
Hate to say this but I would just measure the TS parameters with lab equipment and go from there, picture identifying subs is tricky because sometimes companies will buy slightly modified driver versions that have different power handling, XMAX, etc.
 
#3
sabaspeed521 said:
Hate to say this but I would just measure the TS parameters with lab equipment and go from there, picture identifying subs is tricky because sometimes companies will buy slightly modified driver versions that have different power handling, XMAX, etc.
Click to expand...

So you think there is no other way? Because the mid driver (the 12" one) has the exact same number engraved as the L12-544K RCF that i found online. And they look identical.

Here is a video of my "18 running under about ~550w load. How does it seem to you. Do you think it can take more?

https://www.youtube.com/watch?v=VjWoss3yHAA&list=UUmkR-6Xcfgf2wqiSXCv_4Fw

I recorded this at 60fps (720p) so you should see quiet well 🙂
 
#6
Most woofer failures are from burnt voice coils, though if driven hard enough below Fb (box tuning) excursion can sometimes rip the surround or spider, Xmech or Xlim damage.

If you know what the driver's Xmax is, you can see if that is being exceeded by eye. Excursion looked well under what I would expect Xmech to be in the video.
 
#7
weltersys said:
Most woofer failures are from burnt voice coils, though if driven hard enough below Fb (box tuning) excursion can sometimes rip the surround or spider, Xmech or Xlim damage.

If you know what the driver's Xmax is, you can see if that is being exceeded by eye. Excursion looked well under what I would expect Xmech to be in the video.
Click to expand...

So there is no way to find out the speakers RMS power by pushing it harder and harder... i might melt the voice coil.
Well then i don't know if there is any way to find out witch driver this is. If at least guys from RCF replied my email... L121000 should tell something.

One more question. The system that has been running in the club is:

4x 18" 8ohm woofers.
4x (12+horn)" 8 ohm mid-hii"s

Now those speakers have been running of: 4x500w @ 4ohm amps + 4x900w @4ohm amps.

That means that each mid-hi speaker has been getting about 300w at the amps maximum and each woofer about 550w.

However in case i only had 2x900w @4ohm amps + 2x500w @4ohm amps what i could do is connect 2 + 2 woofers in parralel at the big amp and get 4x450w from it because impedance would go down to 4ohm and then do the same with the mid-hii"s and get 4x250w from only one amp.

Now if i'm not crazy that means that 2 more expensive amps have been bought to get just about 800 more wats at the entire system??
I'm asking this because it seems to me that connecting 8x 8ohm speakers directly to 8 amp channels that are stable @ 4 ohms means using a lot less then their maximum potential? It's kind of non-efficient right? The only good thing is that amps are never going to overheat or be stressed too much right?
 
#8
athlon64 said:
Now if i'm not crazy that means that 2 more expensive amps have been bought to get just about 800 more wats at the entire system??
I'm asking this because it seems to me that connecting 8x 8ohm speakers directly to 8 amp channels that are stable @ 4 ohms means using a lot less then their maximum potential? It's kind of non-efficient right? The only good thing is that amps are never going to overheat or be stressed too much right?
Click to expand...
Less power dissipation does create less heat, so yes, the amps will last longer driving a higher impedance.

Discos often have the amps quite some distance from the speakers, long speaker runs at 8 ohms have a much better damping factor than at 4 ohms.
While the power difference between 8-4 ohm operation is little more than a dB, a reduced damping factor can make a sonic difference in "punch" and detail, damping factors of less than 20 tend to make speakers sound more "flabby".

Art
 
#9
I understand 🙂. So my goal is not allways to torture the amp with the absolute max it can give me. So now i just need to realise witch drivers are my woofers running. To be honest i really don't know how am i going to do that. I hope RCF replies my email.

One more question. My 12"s are RCF L12-544K. Theirs RMS power rating is 300w and AES power rating is 400w. What do you think is the maximum power i can safely give them for playing music. Would they run fine under a 400-450w load?

You can find the specs here: http://static.elitesecurity.org/uploads/2/9/2942696/rcf.pdf

And yes. I'm asking for the max power considering they are not running a full range signal. I set the crossover at 130hz so they don't play anything below.
 
#10
It really depends on the frequency content, HP at 130 I'd say you are very likely to be fine 🙂 Primarily because mid range content isn't usually a constant sine wave like some low bass is and thus your average power dissipated across the Voice coils will be 1/3 or 1/4 what the "peak power" it will be seeing. Still, whenever you reach the maximum power a driver can handle you should be wary of distortion figures (use your ears to determine if it's too much)
 
#11
weltersys said:
Less power dissipation does create less heat, so yes, the amps will last longer driving a higher impedance.

Discos often have the amps quite some distance from the speakers, long speaker runs at 8 ohms have a much better damping factor than at 4 ohms.
While the power difference between 8-4 ohm operation is little more than a dB, a reduced damping factor can make a sonic difference in "punch" and detail, damping factors of less than 20 tend to make speakers sound more "flabby".

Art
Click to expand...

I'd be wary to try and connect "damping factor" with sonic attributes, I've never seen it proven scientifically but am open to references if you have some 🙂.
 
#13
sabaspeed521 said:
I'd be wary to try and connect "damping factor" with sonic attributes, I've never seen it proven scientifically but am open to references if you have some 🙂.
Click to expand...
This is a good article on DF:

http://www.bennettprescott.com/downloads/dampingfactor.pdf

With "normal" wire gauge and short runs, DF is not a concern, but in long runs at low impedance it is. So much so that Harry Witz of dB sound found that running their flown EV MTL quad 18"subs (which for many arenas required over 150' of 12 AWG cable) series parallel 8 ohms rather than 2 ohms gave much better sonic results, even though the amps were capable of considerably less power output into the higher impedance. Back then, I would have done the same, but 80% of my shows were ground stacked with short cables, so it was not worth re-wiring, while dB sound was flying with long cables 80% of the time.

Rog Mogale of Void acoustics has also mentioned similar effects, loss of "punch" in a club system that had lengthened the distance of the wire to the amp room without upgrading the wire gauge.

The practice of putting amps in speaker cabinets eliminates the DF concerns.

That said, with droning bass, DF makes little difference, but with punchy bass, it is fairly easy to tell the difference- put 100 feet of 22 AWG phone cord on a two ohm sub and if you don't hear a difference get back to us (and your audiologist 😉).

Art
 
#15
Seems like I don't have this "damping factor issue" because all the subwoofers I run are 8 ohms, and the 4 ohm subwoofers I'm building will have 25 foot ~12-14 gauge cables. Another issue with running 2 ohm subwoofers is that since you have such a high amount of current there are more line losses and thus they require ridiculously thick copper to keep it "reasonable". 150 feet at 2 ohms (12 gauge) is quite the extreme example but it goes to show that the "wiring guidelines" that suggest gauge to length ratios are something important to consider (my rule of thumb is any run over 50 feet should be a massive cable (greater than 12 gauge) and 14 gauge is plenty good up to 30 feet).
 
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